Lightning-arrester.



R. P. JACKSON.

LIGHTNING ARRESTER.

APPLICATION FILED MAR. 28. 19131 1,217.452. Patented Feb. 27,1917.

WITN ESSES:

E) INVEN 0R ggf/7m ATTORNEY FEE.

TRIO AND MANUFACTURNG COMPNY, 'll- CRGRA..LQN OF EENNSYL'UANIA.

LIGTNING-ARRESTER.

Application filed March 28, 1313.

To all whom t may concern Be it known that I, RAY P. JACKSON, a citizen of the United States, and a resident of Edgewood, in the county of Allegheny and State of lDennsylvania, have invented a new and useful improvement in Lightning- Arresters, of which the following is a speciiication.

My invention relates to devices for protecting electrical circuits and electrical apparatus irom injury by reason of lightning discharges, static disturbances and strains that are occasioned by the flow of high-irequency currents.

My invention relates particularly to lightning arresters of the electrostatic type wherewith apparatus in the disturbed circuit is aorded additional protection by prevent-ing dynamo currents of large values from iiowing to ground in the paths of the arcs established by the discharges.

An object of my invention is to provide in a lightning arrester comprising a series of -air gaps, means whereby dirt and dust are prevented from accumulating and closing up the air gaps and thereby impairing the operating reliability of the arrester. l also provide a high-resistance path in series with the air gaps to limit the yalue of the line current which may How to ground where arcs are established by high-potential discharges.

in the accompanying drawing, the single ligure is a sectional and side view of a device embodying my invention.

Referring to the drawing, the lightning arrester constructed in accordance with my invention comprises a series of superposed and spaced conducting members 1 mounted upon a rod 2, a resistance rod 3 which is connected electrically in series with spark gaps 4C 'formed by the spaced members 1, and a connector 5 Jfor making an electrical connection to ground. When the arrester is intended for outdoor service, a rain shield 6 is added to prevent the air gaps t from being filled with water and thereby make paths of low conductivity. For indoor service, the rain shield may be omitted.

The members 1 are preferably in the form of shallow dished sheets of non-arcing metal, such as cartridge brass, and are downwardly and outwardly flared at their lower edges. By reason of the protection afforded by metallic members 1, the spark gaps 4; are

Specification of Letters Patent.

Patented Feb. 27, 191'?.

Serial No. 757,386.

prevented from being filled with dust and dirt. rlhe flare or the reverse curve formed at the lower edge of each member tends to cause water to flow therefrom and so does not decrease the eectiveness of the spark gaps between adjacent members by lowering their conductivity. intermediate the adjacent members 1, and serving as insulating means therefor, are porcelain was-hers 7. ll pon the upper portion of each washer 7, is termed an annular' shoulder 8 which provides a seat for the metallic member l. By this means, each metallic member 1 is insulated ;t'rcm, and held out of contact with the adjacent metallic members. l prefer that the length or" each spark gap 4 be limited beo d and QU of an inch. Felt washers 10 inserted in the spaces between adjacent porcelain washers 7 so as to relieve them of strains and to provide against their cracking under unusual shocks.

A support 11, preferably made of brass, is secured at its upper end to the lower eX- tremity of the rod il.. An annular flange 12 upon the support serves as a seat for the bottom metallic member 1 of the series surmounting it. In this manner, the bottom metallic member is connected electrically to the support 11.

rlhe resistance rod 3, being provided at each end with a copper shield 1S for insuring good electrical contact, is inclosed in an insulating and protecting tube lei.. Oneend ci' the tube iiiis screwed to the lower portion of the brass support 11. To the other end of the tube is secured a brass member 15 comprising a hook 16 and the connector 5, each of which is in electrical contact with the lower end of the resistance rod 3. A grounded conductor may be connected to the connector 5, thereby furnishing a discharge path over the series of air gaps and through the resistance rod to ground. The purpose of the resistance rod 3 is to limit the value of the current discharges, thereby protecting the generating equipment in the circuit from delivering excessive currents which will tend to flow to ground over the arcs established by the discharges. It is important, in choosing the amount of the ohmic resistance of the rod 3, that it be of the proper value. If a high-resistance rod is used, the high-frequency discharge Ycurrents will pass over the exterior surfaceof the rod in preference to -passing through the rod. This would permit excessive currents to flow from the circuit and may cause dangerous strains to be developed in the generating apparatus.

The arrester may be suspended from a pole of a transmission tower by means of a member 17 which engages the upper portion of the rod 2. Electrical connection between the arrester and a circuit conductor, which is afforded protection by the arrester, is made by means of a branch conductor 1S being screwed to a terminal 19 of the arrester. As sho-wn in the drawing, the member 17 and the terminal 19 may be parts of a single casting. Intermediate the members 17 and a brass washer 20 is supported the rain shield 6. This type of construction connects electrically the branch conductor 18, the rain shield 6 and the top member 'of the series of metallic electrodes 1. vWhen the electrical conditions of the circuit are such that a second series of air gaps and an additional resistance are required, a similar arrester may be added by suspending the same from the hook 16.

lhile I have herein described one embodiment of my invention, it is not intended that my invention, in all its aspects, shall be limited to this particular embodiment, as it will be apparent to anyone skilled in the art, that many changes may be made in the form of myv invention without departing from the spirit thereof.

I claim as my invention:

1. A lightning arrester comprising a plurality of superposed and spaced electrodes, insulating washers interposed between adj acent electrodes, resilient cushions disposed between opposite surfaces of adjacent insulating washers, and a centrally disposed rod extending through said electrodes, insulating washers and resilient cushions in order to hold all of them in fixed relationship to one another.

2. A lightning arrester comprising a plurality of spaced, annular, downwardly and outwardly flared electrodes, insulating washers interposed between adjacent electrodes and provided with shoulders upon which said electrodes are seated, a centrally disposed rod projecting through openings in the electrodes and the washers, and a rain shield for the electrodes.

3. A lightning arrester comprising a plu` rality of spaced, annular, downwardly and outwardly iiared electrodes, insulating washers interposed between adjacent electrodes, means disposed between adjacent insulating washers to absorb mechanical stresses between them, and a centrally disposed support projecting through openings in the electrodes and the insulating washers in order to hold them in fixed relationship to one another.

4i. A lightning arrester'adapted to be connected between Aa line conductor and ground comprising a plurality of superposed, downwardly and outwardly flared electrodes which are spaced to form spark gaps, insulating washers interposed between adj a` cent electrodes, a supporting rod extending through openings in the electrodes and the insulating washers in order to hold them in i fixed relationship to one another, and a resistor connected in series relationship with said spark gaps.

In testimony whereof, I have hereunto subscribed my name this 19th day of March RAY I). JACKSON. Witnesses:

GOLDIE E. MGGEE, B. B. IIINES.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). C. 

